The correct answer is c vaporization.
To explain, condensation is the process where a gas turns into a liquid, typically when it cools down. The reverse of this process would involve a liquid turning back into a gas, which is what vaporization represents. In contrast, freezing (a) is the transition from liquid to solid, sublimation (b) is when a solid changes directly into a gas, and melting (d) is the process of a solid becoming a liquid. Therefore, vaporization is the state change that occurs after condensation, making it the correct answer.